Hospital bed



Sept. 24, 1957 H. D. HELSEL HOSPITAL BED '2 Sheets-Sheet 1 Filed Aug. 3, 1956 INVENTOR. [Va/"old D. H e lse/ A zior'neg P 24, 1957 H. D HELSEL I 2,807,174

HOSPITAL BED Filed Aug. 3. 956 '2 Sheets-Sheet 2 INVENTOR. Har'o/d D. He/se/ A tzforneg United States Patent() 2,807,174 HOSPITAL l3ED Harold D. Helsel, Williamsport, Pa. Application August 3, 1956, Serial No. 602,026

2 Claims. (21. 74- 722 This invention relates to-hospital beds and more particularly to a motor drive for raising-and lowering the head and foot sections thereof and it consists in the constructions, arrangements and combinations herein described and claimed.

More specifically, it is an important object of the invention to provide a motor drive which may be readily installed upon existing hopsital beds'without material alteration in the bed structure and one which may be installed for actuating either the head section or the foot section of the bed to meet the requiremens of different patients.

It is a still further object of the invention to provide a friction drive mechanism which will protect the -motor from excessive strains under operation and one which will prevent the motor from becoming overloaded when initially started, as well as being quiet and smooth during operation, so as to not excite a patient.

A still further object of the invention is the provision of a drive for a hospital bed wherein a slippage may occur between a pair of friction disks and an interposed drive sprocket, and which further includes an adjusting means for varying said slippage to accommodate varying loads disposed upon the head and foot sections of a hospital bed.

Additional objects, advantages and features of invention will be apparent from the following description, considered in conjunction with the accompanying drawings, wherein,

Figure 1 is a side elevation of an invalid or hospital bed having the motor drive installed, the housing for the drive being shown in section.

Figure 2 is a cross section on the line 22 of Figure 1.

Figure 3 is a cross section on the line 33 of Figure 2.

Figure 4 is an exploded side elevation of the friction drive parts being shown in section.

Figure 5 is a side elevation of a drive shaft, in section, for raising and lowering the head or foot sections of a bed. 4

Figure 6 is a fragmentary sectional view illustrating the drive connection between the motor shaft and the shaft for raising and lowering the bed sections.

Figure 7 is a side elevation of a portion of the motor drive shaft.

Figure 8 is a top plan view thereof.

Figure 9 is a fragmentary top plan view of one end of the shaft for raising and lowering the bed sections, and

Figure 10 is a fragmentary side elevation of the operating handle for actuating the shaft of the bed sections when the motor drive is not desired.

There is illustrated an invalid or hospital bed generally indicated by the reference character 10, which comprises an intermediate spring section 11, and hingedly connected end sections 12 and 13, these end sections being raised and lowered as required to meet the needs of a patient.

It should be understood that the sections 12 and 13 are actuated through respective operating means 14, which 2,807,174 Patented Sept. 24, 1,957

are of identical construction, the operating means for raising and lowering section 13 will be described, attention being invited to Figures 1 and 5 of the drawings. The side frame 15 of section 13 is provided with a longitudinally extended slot 16 receiving a pin 17 secured in one end of a link 18, the opposite end of said link being pivotally mounted in a side frame 19 of the bed as at 20.

Movement of the link 18 is effected through telescopically arranged hollow tubing sections 21 and 22. The tubing section 21 is provided interiorly thereof with a fixed bearing 23 and a threaded nut 24, the latter being positioned at the end of the tube which is telescopically positioned within the tube section 22.

The tube section 22 has an interiorly positioned bearing r 25 for mounting a drive shaft 26 having a universal joint 27 having operative connection with a screw shaft 28. The screw shaft 28 is'threadedly engaged in the nut 24 and is rotatably mounted in the bearing 23, the end of the screw shaft being upset as at 29-so that upon rotation of the screw shaft the section 21 may move inwardly and outwardly of the section-22 for raising and lowering the bed section 13.

In order to apply my drive means to the screw shaft 28, the convenitional hand lever (not shown) is removed and instead thereof, an adapter shaft 30 is employed (see Figures 6, 7 and 8) wherein it will be seen that the shaft 30 has a reduced flat extension 31 complemental to a-longitudin'al slot32 formed in the end of the shaft 26, there being a pin 33.extendirig across the slot 32 The extension 31 is formed'with an entrance slot 34 forming communication with a retainer slot 35 (see Figure 7). As clearly shown in Figure 6, a coupling sleeve 36 is mounted on the shaft 26, the extension 31 is then presented in the slot 32 to admit the pin 33 through the entrance slot 34, the adapter shaft 30 then being moved inwardly of the slot so that the pin 33 will occupy a position in the retainer slot 35. The sleeve 36 is then moved to a position overlying the extension 31 and the sleeve is then secured in position by a set screw 37. A sprocket 38 is fixed to the shaft 30 by means of a set screw 39, the shaft therebeyond being supported by a bearing 40 on the bed frame.

The motor generally indicated by the reference character 41 is mounted in a housing 42 which is suitably supported by brackets 43 carried by the frame 44 of the bed. The housing 42 includes a cover 45 permitting access to the drive without removal from the bed, although a wall 46 is provided with an opening 47 permitting adjustment of a friction clutch as will be presently described.

Attention is now invited to Figures 2 and 3 of the drawings for an understanding of the drive 41, which includes a motor 48, the drive shaft of which is provided with a worm gear 49 in mesh with a gear 50 mounted upon a drive shaft 51 extending transversely with respect to the motor and is rotatably supported in spaced bearings 52 mounted upon the floor of the housing.

With reference to Figure 4, it will be seen that the shaft 51 has fixedly mounted thereon a friction disk 53 and a slidably mounted friction disk 54 and between these friction disks there is a freely rotatable sprocket 55. The intermediate portion of the shaft 51 is of greater diameter than the respective ends thereof, this portion having screw threads as at 56. A helical spring 57 encircles the shaft and a knurled nut 58 when engaged with the threads 56 of the shaft will compress the spring so as to urge the sprocket into engagement with the fixed friction disk 53 by virtue of longitudinal movement of the friction disk 54. The degree of movement of the disk 54 will determine the gripping action or slippage upon the sprocket and this can be regulated by varying the tension of the spring 57 through rotation of the nut 58.

7 3 Also mounted within the housing 42 there is a drum 59 rotatably supported between a pair of bearings 60. The drum has keyed thereon a sprocket 61 which is in alignment with the sprocket 55 of the friction drive, and upon opposite sides of the sprocket 60,small sprockets 62 and 62 are keyed to the shaft of the drum. A sprocket chain 63 is trained about the aligned sprockets 55 and 61 so as to impart rotation to the drum 59. In order to effect rotation of the screw shaft 28, a sprocket chain 64 is trained around the sprockets 38 and 62 and preferably a chain guard 65 partially encases the sprocket chain.

In order that the section 12 may be raised and lowered by the drive unit 41, the unit is reversed and mounted upon the opposite side of the bed, in which event, the sprocket 62 will be aligned with the sprocket 38' to receive the chain 64.

The motor 48 may be controlled by means of any suitable starting and reversing switches now available upon the market,

In the event that a motor drive is not desired, the unit may be readily released from the shaft 26 by releasing the coupling 36. An operating lever 66 as shown in Figure 10 may then be employed for engaging the pin 33 for manually raising and lowering the bed sections 12 and 13. 7

While I have shown and described a preferred form of the device, this is by way of illustration only and I consider as my own all such modifications in construction as fairly fall within the scope of the appended claims.

I claim:

1. In a means for raising and lowering hingedly'connected sections of a hospital bed comprising a screw shaft, said shaft having a slotted end, a pin transversely of said and having a gear in mesh with said Worm gear, said transversely extending shaft having a friction clutch consisting of a friction disk fixed to the shaft and a slidable [friction disk, a sprocket interposed between said friction disks, a compression spring on said shaft operative against said slidable friction disk and thereby under normal load to transmit rotation of said shaft and sprocket, a drum rotatably mounted in said housing having a sprocket mounted intermediate the length of the drum, said sprocket being in aii'gnment with the sprocket of the friction clutch, a drive chain trained about said sprockets, respective sprockets being mounted at the ends of the drum, one of said sprockets being in alignment with the sprocket on said coupler shaft and a 'drive chain trained about said sprockets to etfect rotation of said screw shaft.

2. The structure of claim 1, wherein a pair of shafts are employed for raising and lowering respective sections of the bed, said drive means being constructed for selective engagement with either of said shafts.

References Cited in the file of this patent UNITED STATES PATENTS 1,216,084 Dahlberg Feb. 13, 1917 1,880,689 Berry Oct. 4, 1932 2,630,720 Gambill Mar. 10, 1953 

